The present invention relates to an air bag apparatus in which an inflator constituting a gas generating source is inwardly mounted to an air bag, and the air bag is expanded to develop by a gas injected from the inflator.
In the background art, as an air bag of this kind, there is an apparatus described in, for example, Japanese patent application JP-A-2005-170362. That is, according to the air bag apparatus, first, a retainer in a cylindrical shape having a diameter slightly larger than that of an inflator is arranged at inside of the air bag. One end portion in a longitudinal direction of the retainer is exposed to outside of the air bag from an opening portion formed at the air bag, and the inflator is inserted to an inner side of the retainer in the contained state. Further, the inflator is fixed to an end portion of the retainer projected from the air bag by calking. By providing the inflator at the air bag in this way, the air bag is avoided from being damaged in an operation of calking the inflator.
When the inflator is provided in such a mode, since the retainer is projected to outside of the air bag, and therefore, a gas flowing into the air bag through a gap between the retainer and the air bag flows out. Further, depending on the air bag apparatus, there is present an air bag having a specification in which a request for an inner pressure of the air bag is set to be higher than normal, and therefore, in such a case, the flowing out of a gas cannot be disregarded. Although there is also proposed a constitution of pressing the opening portion along with the inflator by a tongue piece extended from the opening portion of the air bag as in an air bag apparatus described in Japanese patent application JP-A-2005-104176 in order to restrain the gas from flowing out, even in such a constitution, only a portion of the opening is closed, and therefore, there still remains a room for improvement.